Agarose waste derived toxicologically screened carbon dots as dual sensor: A mechanistic insight into luminescence and solvatochromic behaviour

Abstract

Fluorescent carbon dots (C-dots) have possessed remarkable and intricate properties which raised concerns and curiosity among researchers in their synthetic aspect. In this outlook, the current work reported the scale-up synthetic protocol for transforming agarose waste, a biologically infectious environmental contaminant, into highly fluorescent C-dots. The formed particles have better control over size, optical and luminescence properties. The value of quantum yield for the developed C-dots was found to be 62%. The detailed mechanistic insight into their optical and solvatochromic behaviour in presence of commercially used solvents has enhanced the knowledge and providing proper justification behind the optical changes in C-dots due to solvation effects. The toxicological screening via multiple assay approach has further attributed towards their biocompatible nature as function of concentration range from 100–5000 ppm. The suggested “waste-to wealth” stratagem is a prosperous step towards tough chore of multiple ion detection of Zn2+ and CO32− ions from aqueous media. The fluorescence enhancement analysis has enumerated the concentration dependency in the range of 50 μM to 30 nM and 10 μM to 60 nM with detection limit value of 0.26 nM and 0.17 nM for Zn2+ and CO32− ions, respectively. The current work provides the way for greener, cost effective and scaled up synthesis of toxicologically screened C-dots for dual fluorescent sensing and opened up the new horizons in environmental remediation applications.